Download Use of Magnesium Oxide-Cement binders for the production of

Use of Magnesium Oxide-Cement binders for the
production of blocks with lightweight aggregates
N. Vlasopoulos & C. Cheeseman
Centre for Environmental Control and Waste Management, Imperial College,
London, SW7 2AZ, UK
ABSTRACT: Magnesium oxide (MgO)-cement (PC) systems are claimed to provide
a sustainable alternative to PC, as MgO is produced by low-temperature (~750oC)
calcination of naturally occurring minerals such as magnesite (MgCO3) or brucite
(Mg(OH)2) precipitated from seawater and brines. In porous or semi porous materials
such as blocks and pavers, magnesium oxide forms carbonates thus reabsorbing the
carbon dioxide produced during calcining. This study has assessed the effect of
reactive MgO and MgO-PC binders on the physical and mechanical properties of
blocks made with lightweight aggregates. The blocks have been cured under either
98% relative humidity or wet-dry cycling to assess the effect of curing conditions on
binder carbonation. MgO has been found to hydrate extensively to form Mg(OH)2,
which was partially carbonated to hydromagnesite (4MgCO3.Mg(OH)2.4H2O). After
90 days curing, MgO samples achieved similar compressive strengths to those
prepared using PC.